TOPIC:

I'm finishing up rebuilding the BS38s on my 750G. One of the main jet plug screws was missing and the other was roached. This screw is M6-0.75x8mm. I can seem to find any M6 bolts in the fine pitch that aren't black oxide. Ideally it would be stainless or plated, but i may just have to buy one of the black ones and paint it or something to keep it from rusting. Any ideas where to find this screw?
These are hands down the weirdest carbs i have ever worked on.

DoctoRot wrote: I'm finishing up rebuilding the BS38s on my 750G. One of the main jet plug screws was missing and the other was roached. This screw is M6-0.75x8mm. I can seem to find any M6 bolts in the fine pitch that aren't black oxide. Ideally it would be stainless or plated, but i may just have to buy one of the black ones and paint it or something to keep it from rusting. Any ideas where to find this screw?
These are hands down the weirdest carbs i have ever worked on.

" main jet plug screws " ?

Do you mean the bowl drain screw? On my BS-38s, the main jets are above the bowl drain screw.


"but i may just have to buy one of the black ones and paint it or something to keep it from rusting."

If it has a black oxide finish, that will keep it from rusting. That's the point of the finish. If you have unfinished carbon steel screws (and you think they will rust) you can black them with Birchwood casey cold blue liquid. I use it on steel gun parts all the time, leaves a dark blue finish.

I think he's referring to #47 in the diagram below. Ed

Have you tried Metric Multistandard, they are out of Hawthorne NY. They sell very high quality German hardware. Not for the faint of heart, but real hardware is never cheep.

Thanks for the replies guys. The black oxide never seems to last. I have bought screws that were black oxide and after a humid month they would rust on the shelf. Other option is i found some drain screws on a Zx-10 that are m6x.75, that i may just cut down to fit. I will also check out metric multistandard.

650ed wrote: I think he's referring to #47 in the diagram below. Ed

Pretty sure that's the bowl drain screw. At least it is on mine.... take that screw out and all the gas runs out....

Yes. I guess they call it the main jet plug because if you remove it you can go through the hole to reach the main jet. BUT, what good would that do anyway since it seems unlikely that a person would try to remove or swap main jets through that little hole? Ed

The main jet can only be accessed through that little hole. It screws into the bottom of the float bowl casting, not the main carburetor body.

Interesting! I learn something every day from this site. Thanks! Ed

Yeah thats why i said they are weird carbs. The jets screw into the float bowl and have a strange float bowl gasket to channel fuel.

DoctoRot wrote: Yeah thats why i said they are weird carbs. The jets screw into the float bowl and have a strange float bowl gasket to channel fuel.

It's actually very cool when you are tuning it up for new headers. Both the main and pilot jet are in the bowl and you can drop the bowls off in about two minutes without removing the carbs if you have the special screwdriver to get at the four bowl screws.

So after searching and searching for an option i had my machinist buddy turn me up some stainless M6 screws with a .75 pitch